Under the Solomon Islands' terms of a draft agreement, China could send police, military personnel and other armed forces to the Solomon Islands "to assist in maintaining social order."
Scott Morrison has called for a May 21 election that will be fought on issues including Chinese economic coercion, climate change and the COVID-19 pandemic.
The announcement comes amid growing concern by the U.S. and its allies about China's growing military assertiveness and Washington's concern of Russia using the weapons in Ukraine.
China has not provided any specifics about what offenses Cheng Lei is accused of committing, who has been held for 19 months on suspicion of relaying state secrets abroad.
The incident, in which someone saw a man in a wetsuit get dragged underwater, is the city's first fatal shark attack since 1963. Beaches are closed while lifeguards patrol for further shark sightings.
Doubly vaccinated travelers will be welcomed starting Feb. 21, nearly two years after it first closed its border. The move is seen as relief for its tourism industry.
The tennis star, who sought a COVID-19 vaccine exemption to play in the tournament, could face deportation again. The battle has sparked protests in the widely vaccinated country.